xref: /linux/include/net/netlink.h (revision a1afb959add1fad43cb337448c244ed70bac3109)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __NET_NETLINK_H
3 #define __NET_NETLINK_H
4 
5 #include <linux/types.h>
6 #include <linux/netlink.h>
7 #include <linux/jiffies.h>
8 #include <linux/in6.h>
9 
10 /* ========================================================================
11  *         Netlink Messages and Attributes Interface (As Seen On TV)
12  * ------------------------------------------------------------------------
13  *                          Messages Interface
14  * ------------------------------------------------------------------------
15  *
16  * Message Format:
17  *    <--- nlmsg_total_size(payload)  --->
18  *    <-- nlmsg_msg_size(payload) ->
19  *   +----------+- - -+-------------+- - -+-------- - -
20  *   | nlmsghdr | Pad |   Payload   | Pad | nlmsghdr
21  *   +----------+- - -+-------------+- - -+-------- - -
22  *   nlmsg_data(nlh)---^                   ^
23  *   nlmsg_next(nlh)-----------------------+
24  *
25  * Payload Format:
26  *    <---------------------- nlmsg_len(nlh) --------------------->
27  *    <------ hdrlen ------>       <- nlmsg_attrlen(nlh, hdrlen) ->
28  *   +----------------------+- - -+--------------------------------+
29  *   |     Family Header    | Pad |           Attributes           |
30  *   +----------------------+- - -+--------------------------------+
31  *   nlmsg_attrdata(nlh, hdrlen)---^
32  *
33  * Data Structures:
34  *   struct nlmsghdr			netlink message header
35  *
36  * Message Construction:
37  *   nlmsg_new()			create a new netlink message
38  *   nlmsg_put()			add a netlink message to an skb
39  *   nlmsg_put_answer()			callback based nlmsg_put()
40  *   nlmsg_end()			finalize netlink message
41  *   nlmsg_get_pos()			return current position in message
42  *   nlmsg_trim()			trim part of message
43  *   nlmsg_cancel()			cancel message construction
44  *   nlmsg_consume()			free a netlink message (expected)
45  *   nlmsg_free()			free a netlink message (drop)
46  *
47  * Message Sending:
48  *   nlmsg_multicast()			multicast message to several groups
49  *   nlmsg_unicast()			unicast a message to a single socket
50  *   nlmsg_notify()			send notification message
51  *
52  * Message Length Calculations:
53  *   nlmsg_msg_size(payload)		length of message w/o padding
54  *   nlmsg_total_size(payload)		length of message w/ padding
55  *   nlmsg_padlen(payload)		length of padding at tail
56  *
57  * Message Payload Access:
58  *   nlmsg_data(nlh)			head of message payload
59  *   nlmsg_len(nlh)			length of message payload
60  *   nlmsg_attrdata(nlh, hdrlen)	head of attributes data
61  *   nlmsg_attrlen(nlh, hdrlen)		length of attributes data
62  *
63  * Message Parsing:
64  *   nlmsg_ok(nlh, remaining)		does nlh fit into remaining bytes?
65  *   nlmsg_next(nlh, remaining)		get next netlink message
66  *   nlmsg_parse()			parse attributes of a message
67  *   nlmsg_find_attr()			find an attribute in a message
68  *   nlmsg_for_each_msg()		loop over all messages
69  *   nlmsg_validate()			validate netlink message incl. attrs
70  *   nlmsg_for_each_attr()		loop over all attributes
71  *
72  * Misc:
73  *   nlmsg_report()			report back to application?
74  *
75  * ------------------------------------------------------------------------
76  *                          Attributes Interface
77  * ------------------------------------------------------------------------
78  *
79  * Attribute Format:
80  *    <------- nla_total_size(payload) ------->
81  *    <---- nla_attr_size(payload) ----->
82  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
83  *   |  Header  | Pad |     Payload      | Pad |  Header
84  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
85  *                     <- nla_len(nla) ->      ^
86  *   nla_data(nla)----^                        |
87  *   nla_next(nla)-----------------------------'
88  *
89  * Data Structures:
90  *   struct nlattr			netlink attribute header
91  *
92  * Attribute Construction:
93  *   nla_reserve(skb, type, len)	reserve room for an attribute
94  *   nla_reserve_nohdr(skb, len)	reserve room for an attribute w/o hdr
95  *   nla_put(skb, type, len, data)	add attribute to skb
96  *   nla_put_nohdr(skb, len, data)	add attribute w/o hdr
97  *   nla_append(skb, len, data)		append data to skb
98  *
99  * Attribute Construction for Basic Types:
100  *   nla_put_u8(skb, type, value)	add u8 attribute to skb
101  *   nla_put_u16(skb, type, value)	add u16 attribute to skb
102  *   nla_put_u32(skb, type, value)	add u32 attribute to skb
103  *   nla_put_u64_64bit(skb, type,
104  *                     value, padattr)	add u64 attribute to skb
105  *   nla_put_s8(skb, type, value)	add s8 attribute to skb
106  *   nla_put_s16(skb, type, value)	add s16 attribute to skb
107  *   nla_put_s32(skb, type, value)	add s32 attribute to skb
108  *   nla_put_s64(skb, type, value,
109  *               padattr)		add s64 attribute to skb
110  *   nla_put_string(skb, type, str)	add string attribute to skb
111  *   nla_put_flag(skb, type)		add flag attribute to skb
112  *   nla_put_msecs(skb, type, jiffies,
113  *                 padattr)		add msecs attribute to skb
114  *   nla_put_in_addr(skb, type, addr)	add IPv4 address attribute to skb
115  *   nla_put_in6_addr(skb, type, addr)	add IPv6 address attribute to skb
116  *
117  * Nested Attributes Construction:
118  *   nla_nest_start(skb, type)		start a nested attribute
119  *   nla_nest_end(skb, nla)		finalize a nested attribute
120  *   nla_nest_cancel(skb, nla)		cancel nested attribute construction
121  *
122  * Attribute Length Calculations:
123  *   nla_attr_size(payload)		length of attribute w/o padding
124  *   nla_total_size(payload)		length of attribute w/ padding
125  *   nla_padlen(payload)		length of padding
126  *
127  * Attribute Payload Access:
128  *   nla_data(nla)			head of attribute payload
129  *   nla_len(nla)			length of attribute payload
130  *
131  * Attribute Payload Access for Basic Types:
132  *   nla_get_uint(nla)			get payload for a uint attribute
133  *   nla_get_sint(nla)			get payload for a sint attribute
134  *   nla_get_u8(nla)			get payload for a u8 attribute
135  *   nla_get_u16(nla)			get payload for a u16 attribute
136  *   nla_get_u32(nla)			get payload for a u32 attribute
137  *   nla_get_u64(nla)			get payload for a u64 attribute
138  *   nla_get_s8(nla)			get payload for a s8 attribute
139  *   nla_get_s16(nla)			get payload for a s16 attribute
140  *   nla_get_s32(nla)			get payload for a s32 attribute
141  *   nla_get_s64(nla)			get payload for a s64 attribute
142  *   nla_get_flag(nla)			return 1 if flag is true
143  *   nla_get_msecs(nla)			get payload for a msecs attribute
144  *
145  * Attribute Misc:
146  *   nla_memcpy(dest, nla, count)	copy attribute into memory
147  *   nla_memcmp(nla, data, size)	compare attribute with memory area
148  *   nla_strscpy(dst, nla, size)	copy attribute to a sized string
149  *   nla_strcmp(nla, str)		compare attribute with string
150  *
151  * Attribute Parsing:
152  *   nla_ok(nla, remaining)		does nla fit into remaining bytes?
153  *   nla_next(nla, remaining)		get next netlink attribute
154  *   nla_validate()			validate a stream of attributes
155  *   nla_validate_nested()		validate a stream of nested attributes
156  *   nla_find()				find attribute in stream of attributes
157  *   nla_find_nested()			find attribute in nested attributes
158  *   nla_parse()			parse and validate stream of attrs
159  *   nla_parse_nested()			parse nested attributes
160  *   nla_for_each_attr()		loop over all attributes
161  *   nla_for_each_attr_type()		loop over all attributes with the
162  *					given type
163  *   nla_for_each_nested()		loop over the nested attributes
164  *   nla_for_each_nested_type()		loop over the nested attributes with
165  *					the given type
166  *=========================================================================
167  */
168 
169  /**
170   * Standard attribute types to specify validation policy
171   */
172 enum {
173 	NLA_UNSPEC,
174 	NLA_U8,
175 	NLA_U16,
176 	NLA_U32,
177 	NLA_U64,
178 	NLA_STRING,
179 	NLA_FLAG,
180 	NLA_MSECS,
181 	NLA_NESTED,
182 	NLA_NESTED_ARRAY,
183 	NLA_NUL_STRING,
184 	NLA_BINARY,
185 	NLA_S8,
186 	NLA_S16,
187 	NLA_S32,
188 	NLA_S64,
189 	NLA_BITFIELD32,
190 	NLA_REJECT,
191 	NLA_BE16,
192 	NLA_BE32,
193 	NLA_SINT,
194 	NLA_UINT,
195 	__NLA_TYPE_MAX,
196 };
197 
198 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
199 
200 struct netlink_range_validation {
201 	u64 min, max;
202 };
203 
204 struct netlink_range_validation_signed {
205 	s64 min, max;
206 };
207 
208 enum nla_policy_validation {
209 	NLA_VALIDATE_NONE,
210 	NLA_VALIDATE_RANGE,
211 	NLA_VALIDATE_RANGE_WARN_TOO_LONG,
212 	NLA_VALIDATE_MIN,
213 	NLA_VALIDATE_MAX,
214 	NLA_VALIDATE_MASK,
215 	NLA_VALIDATE_RANGE_PTR,
216 	NLA_VALIDATE_FUNCTION,
217 };
218 
219 /**
220  * struct nla_policy - attribute validation policy
221  * @type: Type of attribute or NLA_UNSPEC
222  * @validation_type: type of attribute validation done in addition to
223  *	type-specific validation (e.g. range, function call), see
224  *	&enum nla_policy_validation
225  * @len: Type specific length of payload
226  *
227  * Policies are defined as arrays of this struct, the array must be
228  * accessible by attribute type up to the highest identifier to be expected.
229  *
230  * Meaning of `len' field:
231  *    NLA_STRING           Maximum length of string
232  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
233  *    NLA_FLAG             Unused
234  *    NLA_BINARY           Maximum length of attribute payload
235  *                         (but see also below with the validation type)
236  *    NLA_NESTED,
237  *    NLA_NESTED_ARRAY     Length verification is done by checking len of
238  *                         nested header (or empty); len field is used if
239  *                         nested_policy is also used, for the max attr
240  *                         number in the nested policy.
241  *    NLA_SINT, NLA_UINT,
242  *    NLA_U8, NLA_U16,
243  *    NLA_U32, NLA_U64,
244  *    NLA_S8, NLA_S16,
245  *    NLA_S32, NLA_S64,
246  *    NLA_BE16, NLA_BE32,
247  *    NLA_MSECS            Leaving the length field zero will verify the
248  *                         given type fits, using it verifies minimum length
249  *                         just like "All other"
250  *    NLA_BITFIELD32       Unused
251  *    NLA_REJECT           Unused
252  *    All other            Minimum length of attribute payload
253  *
254  * Meaning of validation union:
255  *    NLA_BITFIELD32       This is a 32-bit bitmap/bitselector attribute and
256  *                         `bitfield32_valid' is the u32 value of valid flags
257  *    NLA_REJECT           This attribute is always rejected and `reject_message'
258  *                         may point to a string to report as the error instead
259  *                         of the generic one in extended ACK.
260  *    NLA_NESTED           `nested_policy' to a nested policy to validate, must
261  *                         also set `len' to the max attribute number. Use the
262  *                         provided NLA_POLICY_NESTED() macro.
263  *                         Note that nla_parse() will validate, but of course not
264  *                         parse, the nested sub-policies.
265  *    NLA_NESTED_ARRAY     `nested_policy' points to a nested policy to validate,
266  *                         must also set `len' to the max attribute number. Use
267  *                         the provided NLA_POLICY_NESTED_ARRAY() macro.
268  *                         The difference to NLA_NESTED is the structure:
269  *                         NLA_NESTED has the nested attributes directly inside
270  *                         while an array has the nested attributes at another
271  *                         level down and the attribute types directly in the
272  *                         nesting don't matter.
273  *    NLA_UINT,
274  *    NLA_U8,
275  *    NLA_U16,
276  *    NLA_U32,
277  *    NLA_U64,
278  *    NLA_BE16,
279  *    NLA_BE32,
280  *    NLA_SINT,
281  *    NLA_S8,
282  *    NLA_S16,
283  *    NLA_S32,
284  *    NLA_S64              The `min' and `max' fields are used depending on the
285  *                         validation_type field, if that is min/max/range then
286  *                         the min, max or both are used (respectively) to check
287  *                         the value of the integer attribute.
288  *                         Note that in the interest of code simplicity and
289  *                         struct size both limits are s16, so you cannot
290  *                         enforce a range that doesn't fall within the range
291  *                         of s16 - do that using the NLA_POLICY_FULL_RANGE()
292  *                         or NLA_POLICY_FULL_RANGE_SIGNED() macros instead.
293  *                         Use the NLA_POLICY_MIN(), NLA_POLICY_MAX() and
294  *                         NLA_POLICY_RANGE() macros.
295  *    NLA_UINT,
296  *    NLA_U8,
297  *    NLA_U16,
298  *    NLA_U32,
299  *    NLA_U64              If the validation_type field instead is set to
300  *                         NLA_VALIDATE_RANGE_PTR, `range' must be a pointer
301  *                         to a struct netlink_range_validation that indicates
302  *                         the min/max values.
303  *                         Use NLA_POLICY_FULL_RANGE().
304  *    NLA_SINT,
305  *    NLA_S8,
306  *    NLA_S16,
307  *    NLA_S32,
308  *    NLA_S64              If the validation_type field instead is set to
309  *                         NLA_VALIDATE_RANGE_PTR, `range_signed' must be a
310  *                         pointer to a struct netlink_range_validation_signed
311  *                         that indicates the min/max values.
312  *                         Use NLA_POLICY_FULL_RANGE_SIGNED().
313  *
314  *    NLA_BINARY           If the validation type is like the ones for integers
315  *                         above, then the min/max length (not value like for
316  *                         integers) of the attribute is enforced.
317  *
318  *    All other            Unused - but note that it's a union
319  *
320  * Meaning of `validate' field, use via NLA_POLICY_VALIDATE_FN:
321  *    NLA_BINARY           Validation function called for the attribute.
322  *    All other            Unused - but note that it's a union
323  *
324  * Example:
325  *
326  * static const u32 myvalidflags = 0xff231023;
327  *
328  * static const struct nla_policy my_policy[ATTR_MAX+1] = {
329  * 	[ATTR_FOO] = { .type = NLA_U16 },
330  *	[ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
331  *	[ATTR_BAZ] = NLA_POLICY_EXACT_LEN(sizeof(struct mystruct)),
332  *	[ATTR_GOO] = NLA_POLICY_BITFIELD32(myvalidflags),
333  * };
334  */
335 struct nla_policy {
336 	u8		type;
337 	u8		validation_type;
338 	u16		len;
339 	union {
340 		/**
341 		 * @strict_start_type: first attribute to validate strictly
342 		 *
343 		 * This entry is special, and used for the attribute at index 0
344 		 * only, and specifies special data about the policy, namely it
345 		 * specifies the "boundary type" where strict length validation
346 		 * starts for any attribute types >= this value, also, strict
347 		 * nesting validation starts here.
348 		 *
349 		 * Additionally, it means that NLA_UNSPEC is actually NLA_REJECT
350 		 * for any types >= this, so need to use NLA_POLICY_MIN_LEN() to
351 		 * get the previous pure { .len = xyz } behaviour. The advantage
352 		 * of this is that types not specified in the policy will be
353 		 * rejected.
354 		 *
355 		 * For completely new families it should be set to 1 so that the
356 		 * validation is enforced for all attributes. For existing ones
357 		 * it should be set at least when new attributes are added to
358 		 * the enum used by the policy, and be set to the new value that
359 		 * was added to enforce strict validation from thereon.
360 		 */
361 		u16 strict_start_type;
362 
363 		/* private: use NLA_POLICY_*() to set */
364 		const u32 bitfield32_valid;
365 		const u32 mask;
366 		const char *reject_message;
367 		const struct nla_policy *nested_policy;
368 		const struct netlink_range_validation *range;
369 		const struct netlink_range_validation_signed *range_signed;
370 		struct {
371 			s16 min, max;
372 		};
373 		int (*validate)(const struct nlattr *attr,
374 				struct netlink_ext_ack *extack);
375 	};
376 };
377 
378 #define NLA_POLICY_ETH_ADDR		NLA_POLICY_EXACT_LEN(ETH_ALEN)
379 #define NLA_POLICY_ETH_ADDR_COMPAT	NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN)
380 
381 #define _NLA_POLICY_NESTED(maxattr, policy) \
382 	{ .type = NLA_NESTED, .nested_policy = policy, .len = maxattr }
383 #define _NLA_POLICY_NESTED_ARRAY(maxattr, policy) \
384 	{ .type = NLA_NESTED_ARRAY, .nested_policy = policy, .len = maxattr }
385 #define NLA_POLICY_NESTED(policy) \
386 	_NLA_POLICY_NESTED(ARRAY_SIZE(policy) - 1, policy)
387 #define NLA_POLICY_NESTED_ARRAY(policy) \
388 	_NLA_POLICY_NESTED_ARRAY(ARRAY_SIZE(policy) - 1, policy)
389 #define NLA_POLICY_BITFIELD32(valid) \
390 	{ .type = NLA_BITFIELD32, .bitfield32_valid = valid }
391 
392 #define __NLA_IS_UINT_TYPE(tp)					\
393 	(tp == NLA_U8 || tp == NLA_U16 || tp == NLA_U32 ||	\
394 	 tp == NLA_U64 || tp == NLA_UINT ||			\
395 	 tp == NLA_BE16 || tp == NLA_BE32)
396 #define __NLA_IS_SINT_TYPE(tp)						\
397 	(tp == NLA_S8 || tp == NLA_S16 || tp == NLA_S32 || tp == NLA_S64 || \
398 	 tp == NLA_SINT)
399 
400 #define __NLA_ENSURE(condition) BUILD_BUG_ON_ZERO(!(condition))
401 #define NLA_ENSURE_UINT_TYPE(tp)			\
402 	(__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp)) + tp)
403 #define NLA_ENSURE_UINT_OR_BINARY_TYPE(tp)		\
404 	(__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp) ||	\
405 		      tp == NLA_MSECS ||		\
406 		      tp == NLA_BINARY) + tp)
407 #define NLA_ENSURE_SINT_TYPE(tp)			\
408 	(__NLA_ENSURE(__NLA_IS_SINT_TYPE(tp)) + tp)
409 #define NLA_ENSURE_INT_OR_BINARY_TYPE(tp)		\
410 	(__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp) ||		\
411 		      __NLA_IS_SINT_TYPE(tp) ||		\
412 		      tp == NLA_MSECS ||		\
413 		      tp == NLA_BINARY) + tp)
414 #define NLA_ENSURE_NO_VALIDATION_PTR(tp)		\
415 	(__NLA_ENSURE(tp != NLA_BITFIELD32 &&		\
416 		      tp != NLA_REJECT &&		\
417 		      tp != NLA_NESTED &&		\
418 		      tp != NLA_NESTED_ARRAY) + tp)
419 
420 #define NLA_POLICY_RANGE(tp, _min, _max) {		\
421 	.type = NLA_ENSURE_INT_OR_BINARY_TYPE(tp),	\
422 	.validation_type = NLA_VALIDATE_RANGE,		\
423 	.min = _min,					\
424 	.max = _max					\
425 }
426 
427 #define NLA_POLICY_FULL_RANGE(tp, _range) {		\
428 	.type = NLA_ENSURE_UINT_OR_BINARY_TYPE(tp),	\
429 	.validation_type = NLA_VALIDATE_RANGE_PTR,	\
430 	.range = _range,				\
431 }
432 
433 #define NLA_POLICY_FULL_RANGE_SIGNED(tp, _range) {	\
434 	.type = NLA_ENSURE_SINT_TYPE(tp),		\
435 	.validation_type = NLA_VALIDATE_RANGE_PTR,	\
436 	.range_signed = _range,				\
437 }
438 
439 #define NLA_POLICY_MIN(tp, _min) {			\
440 	.type = NLA_ENSURE_INT_OR_BINARY_TYPE(tp),	\
441 	.validation_type = NLA_VALIDATE_MIN,		\
442 	.min = _min,					\
443 }
444 
445 #define NLA_POLICY_MAX(tp, _max) {			\
446 	.type = NLA_ENSURE_INT_OR_BINARY_TYPE(tp),	\
447 	.validation_type = NLA_VALIDATE_MAX,		\
448 	.max = _max,					\
449 }
450 
451 #define NLA_POLICY_MASK(tp, _mask) {			\
452 	.type = NLA_ENSURE_UINT_TYPE(tp),		\
453 	.validation_type = NLA_VALIDATE_MASK,		\
454 	.mask = _mask,					\
455 }
456 
457 #define NLA_POLICY_VALIDATE_FN(tp, fn, ...) {		\
458 	.type = NLA_ENSURE_NO_VALIDATION_PTR(tp),	\
459 	.validation_type = NLA_VALIDATE_FUNCTION,	\
460 	.validate = fn,					\
461 	.len = __VA_ARGS__ + 0,				\
462 }
463 
464 #define NLA_POLICY_EXACT_LEN(_len)	NLA_POLICY_RANGE(NLA_BINARY, _len, _len)
465 #define NLA_POLICY_EXACT_LEN_WARN(_len) {			\
466 	.type = NLA_BINARY,					\
467 	.validation_type = NLA_VALIDATE_RANGE_WARN_TOO_LONG,	\
468 	.min = _len,						\
469 	.max = _len						\
470 }
471 #define NLA_POLICY_MIN_LEN(_len)	NLA_POLICY_MIN(NLA_BINARY, _len)
472 #define NLA_POLICY_MAX_LEN(_len)	NLA_POLICY_MAX(NLA_BINARY, _len)
473 
474 /**
475  * struct nl_info - netlink source information
476  * @nlh: Netlink message header of original request
477  * @nl_net: Network namespace
478  * @portid: Netlink PORTID of requesting application
479  * @skip_notify: Skip netlink notifications to user space
480  * @skip_notify_kernel: Skip selected in-kernel notifications
481  */
482 struct nl_info {
483 	struct nlmsghdr		*nlh;
484 	struct net		*nl_net;
485 	u32			portid;
486 	u8			skip_notify:1,
487 				skip_notify_kernel:1;
488 };
489 
490 /**
491  * enum netlink_validation - netlink message/attribute validation levels
492  * @NL_VALIDATE_LIBERAL: Old-style "be liberal" validation, not caring about
493  *	extra data at the end of the message, attributes being longer than
494  *	they should be, or unknown attributes being present.
495  * @NL_VALIDATE_TRAILING: Reject junk data encountered after attribute parsing.
496  * @NL_VALIDATE_MAXTYPE: Reject attributes > max type; Together with _TRAILING
497  *	this is equivalent to the old nla_parse_strict()/nlmsg_parse_strict().
498  * @NL_VALIDATE_UNSPEC: Reject attributes with NLA_UNSPEC in the policy.
499  *	This can safely be set by the kernel when the given policy has no
500  *	NLA_UNSPEC anymore, and can thus be used to ensure policy entries
501  *	are enforced going forward.
502  * @NL_VALIDATE_STRICT_ATTRS: strict attribute policy parsing (e.g.
503  *	U8, U16, U32 must have exact size, etc.)
504  * @NL_VALIDATE_NESTED: Check that NLA_F_NESTED is set for NLA_NESTED(_ARRAY)
505  *	and unset for other policies.
506  */
507 enum netlink_validation {
508 	NL_VALIDATE_LIBERAL = 0,
509 	NL_VALIDATE_TRAILING = BIT(0),
510 	NL_VALIDATE_MAXTYPE = BIT(1),
511 	NL_VALIDATE_UNSPEC = BIT(2),
512 	NL_VALIDATE_STRICT_ATTRS = BIT(3),
513 	NL_VALIDATE_NESTED = BIT(4),
514 };
515 
516 #define NL_VALIDATE_DEPRECATED_STRICT (NL_VALIDATE_TRAILING |\
517 				       NL_VALIDATE_MAXTYPE)
518 #define NL_VALIDATE_STRICT (NL_VALIDATE_TRAILING |\
519 			    NL_VALIDATE_MAXTYPE |\
520 			    NL_VALIDATE_UNSPEC |\
521 			    NL_VALIDATE_STRICT_ATTRS |\
522 			    NL_VALIDATE_NESTED)
523 
524 int netlink_rcv_skb(struct sk_buff *skb,
525 		    int (*cb)(struct sk_buff *, struct nlmsghdr *,
526 			      struct netlink_ext_ack *));
527 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
528 		 unsigned int group, int report, gfp_t flags);
529 
530 int __nla_validate(const struct nlattr *head, int len, int maxtype,
531 		   const struct nla_policy *policy, unsigned int validate,
532 		   struct netlink_ext_ack *extack);
533 int __nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
534 		int len, const struct nla_policy *policy, unsigned int validate,
535 		struct netlink_ext_ack *extack);
536 int nla_policy_len(const struct nla_policy *, int);
537 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
538 ssize_t nla_strscpy(char *dst, const struct nlattr *nla, size_t dstsize);
539 char *nla_strdup(const struct nlattr *nla, gfp_t flags);
540 int nla_memcpy(void *dest, const struct nlattr *src, int count);
541 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
542 int nla_strcmp(const struct nlattr *nla, const char *str);
543 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
544 struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
545 				   int attrlen, int padattr);
546 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
547 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
548 struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype,
549 				 int attrlen, int padattr);
550 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
551 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
552 	       const void *data);
553 void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
554 		     const void *data, int padattr);
555 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
556 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
557 int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
558 		  const void *data, int padattr);
559 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
560 int nla_append(struct sk_buff *skb, int attrlen, const void *data);
561 
562 /**************************************************************************
563  * Netlink Messages
564  **************************************************************************/
565 
566 /**
567  * nlmsg_msg_size - length of netlink message not including padding
568  * @payload: length of message payload
569  */
570 static inline int nlmsg_msg_size(int payload)
571 {
572 	return NLMSG_HDRLEN + payload;
573 }
574 
575 /**
576  * nlmsg_total_size - length of netlink message including padding
577  * @payload: length of message payload
578  */
579 static inline int nlmsg_total_size(int payload)
580 {
581 	return NLMSG_ALIGN(nlmsg_msg_size(payload));
582 }
583 
584 /**
585  * nlmsg_padlen - length of padding at the message's tail
586  * @payload: length of message payload
587  */
588 static inline int nlmsg_padlen(int payload)
589 {
590 	return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
591 }
592 
593 /**
594  * nlmsg_data - head of message payload
595  * @nlh: netlink message header
596  */
597 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
598 {
599 	return (unsigned char *) nlh + NLMSG_HDRLEN;
600 }
601 
602 /**
603  * nlmsg_len - length of message payload
604  * @nlh: netlink message header
605  */
606 static inline int nlmsg_len(const struct nlmsghdr *nlh)
607 {
608 	return nlh->nlmsg_len - NLMSG_HDRLEN;
609 }
610 
611 /**
612  * nlmsg_attrdata - head of attributes data
613  * @nlh: netlink message header
614  * @hdrlen: length of family specific header
615  */
616 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
617 					    int hdrlen)
618 {
619 	unsigned char *data = nlmsg_data(nlh);
620 	return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
621 }
622 
623 /**
624  * nlmsg_attrlen - length of attributes data
625  * @nlh: netlink message header
626  * @hdrlen: length of family specific header
627  */
628 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
629 {
630 	return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
631 }
632 
633 /**
634  * nlmsg_ok - check if the netlink message fits into the remaining bytes
635  * @nlh: netlink message header
636  * @remaining: number of bytes remaining in message stream
637  */
638 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
639 {
640 	return (remaining >= (int) sizeof(struct nlmsghdr) &&
641 		nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
642 		nlh->nlmsg_len <= remaining);
643 }
644 
645 /**
646  * nlmsg_next - next netlink message in message stream
647  * @nlh: netlink message header
648  * @remaining: number of bytes remaining in message stream
649  *
650  * Returns the next netlink message in the message stream and
651  * decrements remaining by the size of the current message.
652  */
653 static inline struct nlmsghdr *
654 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
655 {
656 	int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
657 
658 	*remaining -= totlen;
659 
660 	return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
661 }
662 
663 /**
664  * nla_parse - Parse a stream of attributes into a tb buffer
665  * @tb: destination array with maxtype+1 elements
666  * @maxtype: maximum attribute type to be expected
667  * @head: head of attribute stream
668  * @len: length of attribute stream
669  * @policy: validation policy
670  * @extack: extended ACK pointer
671  *
672  * Parses a stream of attributes and stores a pointer to each attribute in
673  * the tb array accessible via the attribute type. Attributes with a type
674  * exceeding maxtype will be rejected, policy must be specified, attributes
675  * will be validated in the strictest way possible.
676  *
677  * Returns 0 on success or a negative error code.
678  */
679 static inline int nla_parse(struct nlattr **tb, int maxtype,
680 			    const struct nlattr *head, int len,
681 			    const struct nla_policy *policy,
682 			    struct netlink_ext_ack *extack)
683 {
684 	return __nla_parse(tb, maxtype, head, len, policy,
685 			   NL_VALIDATE_STRICT, extack);
686 }
687 
688 /**
689  * nla_parse_deprecated - Parse a stream of attributes into a tb buffer
690  * @tb: destination array with maxtype+1 elements
691  * @maxtype: maximum attribute type to be expected
692  * @head: head of attribute stream
693  * @len: length of attribute stream
694  * @policy: validation policy
695  * @extack: extended ACK pointer
696  *
697  * Parses a stream of attributes and stores a pointer to each attribute in
698  * the tb array accessible via the attribute type. Attributes with a type
699  * exceeding maxtype will be ignored and attributes from the policy are not
700  * always strictly validated (only for new attributes).
701  *
702  * Returns 0 on success or a negative error code.
703  */
704 static inline int nla_parse_deprecated(struct nlattr **tb, int maxtype,
705 				       const struct nlattr *head, int len,
706 				       const struct nla_policy *policy,
707 				       struct netlink_ext_ack *extack)
708 {
709 	return __nla_parse(tb, maxtype, head, len, policy,
710 			   NL_VALIDATE_LIBERAL, extack);
711 }
712 
713 /**
714  * nla_parse_deprecated_strict - Parse a stream of attributes into a tb buffer
715  * @tb: destination array with maxtype+1 elements
716  * @maxtype: maximum attribute type to be expected
717  * @head: head of attribute stream
718  * @len: length of attribute stream
719  * @policy: validation policy
720  * @extack: extended ACK pointer
721  *
722  * Parses a stream of attributes and stores a pointer to each attribute in
723  * the tb array accessible via the attribute type. Attributes with a type
724  * exceeding maxtype will be rejected as well as trailing data, but the
725  * policy is not completely strictly validated (only for new attributes).
726  *
727  * Returns 0 on success or a negative error code.
728  */
729 static inline int nla_parse_deprecated_strict(struct nlattr **tb, int maxtype,
730 					      const struct nlattr *head,
731 					      int len,
732 					      const struct nla_policy *policy,
733 					      struct netlink_ext_ack *extack)
734 {
735 	return __nla_parse(tb, maxtype, head, len, policy,
736 			   NL_VALIDATE_DEPRECATED_STRICT, extack);
737 }
738 
739 /**
740  * __nlmsg_parse - parse attributes of a netlink message
741  * @nlh: netlink message header
742  * @hdrlen: length of family specific header
743  * @tb: destination array with maxtype+1 elements
744  * @maxtype: maximum attribute type to be expected
745  * @policy: validation policy
746  * @validate: validation strictness
747  * @extack: extended ACK report struct
748  *
749  * See nla_parse()
750  */
751 static inline int __nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
752 				struct nlattr *tb[], int maxtype,
753 				const struct nla_policy *policy,
754 				unsigned int validate,
755 				struct netlink_ext_ack *extack)
756 {
757 	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {
758 		NL_SET_ERR_MSG(extack, "Invalid header length");
759 		return -EINVAL;
760 	}
761 
762 	return __nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
763 			   nlmsg_attrlen(nlh, hdrlen), policy, validate,
764 			   extack);
765 }
766 
767 /**
768  * nlmsg_parse - parse attributes of a netlink message
769  * @nlh: netlink message header
770  * @hdrlen: length of family specific header
771  * @tb: destination array with maxtype+1 elements
772  * @maxtype: maximum attribute type to be expected
773  * @policy: validation policy
774  * @extack: extended ACK report struct
775  *
776  * See nla_parse()
777  */
778 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
779 			      struct nlattr *tb[], int maxtype,
780 			      const struct nla_policy *policy,
781 			      struct netlink_ext_ack *extack)
782 {
783 	return __nlmsg_parse(nlh, hdrlen, tb, maxtype, policy,
784 			     NL_VALIDATE_STRICT, extack);
785 }
786 
787 /**
788  * nlmsg_parse_deprecated - parse attributes of a netlink message
789  * @nlh: netlink message header
790  * @hdrlen: length of family specific header
791  * @tb: destination array with maxtype+1 elements
792  * @maxtype: maximum attribute type to be expected
793  * @policy: validation policy
794  * @extack: extended ACK report struct
795  *
796  * See nla_parse_deprecated()
797  */
798 static inline int nlmsg_parse_deprecated(const struct nlmsghdr *nlh, int hdrlen,
799 					 struct nlattr *tb[], int maxtype,
800 					 const struct nla_policy *policy,
801 					 struct netlink_ext_ack *extack)
802 {
803 	return __nlmsg_parse(nlh, hdrlen, tb, maxtype, policy,
804 			     NL_VALIDATE_LIBERAL, extack);
805 }
806 
807 /**
808  * nlmsg_parse_deprecated_strict - parse attributes of a netlink message
809  * @nlh: netlink message header
810  * @hdrlen: length of family specific header
811  * @tb: destination array with maxtype+1 elements
812  * @maxtype: maximum attribute type to be expected
813  * @policy: validation policy
814  * @extack: extended ACK report struct
815  *
816  * See nla_parse_deprecated_strict()
817  */
818 static inline int
819 nlmsg_parse_deprecated_strict(const struct nlmsghdr *nlh, int hdrlen,
820 			      struct nlattr *tb[], int maxtype,
821 			      const struct nla_policy *policy,
822 			      struct netlink_ext_ack *extack)
823 {
824 	return __nlmsg_parse(nlh, hdrlen, tb, maxtype, policy,
825 			     NL_VALIDATE_DEPRECATED_STRICT, extack);
826 }
827 
828 /**
829  * nlmsg_find_attr - find a specific attribute in a netlink message
830  * @nlh: netlink message header
831  * @hdrlen: length of family specific header
832  * @attrtype: type of attribute to look for
833  *
834  * Returns the first attribute which matches the specified type.
835  */
836 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
837 					     int hdrlen, int attrtype)
838 {
839 	return nla_find(nlmsg_attrdata(nlh, hdrlen),
840 			nlmsg_attrlen(nlh, hdrlen), attrtype);
841 }
842 
843 /**
844  * nla_validate_deprecated - Validate a stream of attributes
845  * @head: head of attribute stream
846  * @len: length of attribute stream
847  * @maxtype: maximum attribute type to be expected
848  * @policy: validation policy
849  * @extack: extended ACK report struct
850  *
851  * Validates all attributes in the specified attribute stream against the
852  * specified policy. Validation is done in liberal mode.
853  * See documentation of struct nla_policy for more details.
854  *
855  * Returns 0 on success or a negative error code.
856  */
857 static inline int nla_validate_deprecated(const struct nlattr *head, int len,
858 					  int maxtype,
859 					  const struct nla_policy *policy,
860 					  struct netlink_ext_ack *extack)
861 {
862 	return __nla_validate(head, len, maxtype, policy, NL_VALIDATE_LIBERAL,
863 			      extack);
864 }
865 
866 /**
867  * nla_validate - Validate a stream of attributes
868  * @head: head of attribute stream
869  * @len: length of attribute stream
870  * @maxtype: maximum attribute type to be expected
871  * @policy: validation policy
872  * @extack: extended ACK report struct
873  *
874  * Validates all attributes in the specified attribute stream against the
875  * specified policy. Validation is done in strict mode.
876  * See documentation of struct nla_policy for more details.
877  *
878  * Returns 0 on success or a negative error code.
879  */
880 static inline int nla_validate(const struct nlattr *head, int len, int maxtype,
881 			       const struct nla_policy *policy,
882 			       struct netlink_ext_ack *extack)
883 {
884 	return __nla_validate(head, len, maxtype, policy, NL_VALIDATE_STRICT,
885 			      extack);
886 }
887 
888 /**
889  * nlmsg_validate_deprecated - validate a netlink message including attributes
890  * @nlh: netlinket message header
891  * @hdrlen: length of family specific header
892  * @maxtype: maximum attribute type to be expected
893  * @policy: validation policy
894  * @extack: extended ACK report struct
895  */
896 static inline int nlmsg_validate_deprecated(const struct nlmsghdr *nlh,
897 					    int hdrlen, int maxtype,
898 					    const struct nla_policy *policy,
899 					    struct netlink_ext_ack *extack)
900 {
901 	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
902 		return -EINVAL;
903 
904 	return __nla_validate(nlmsg_attrdata(nlh, hdrlen),
905 			      nlmsg_attrlen(nlh, hdrlen), maxtype,
906 			      policy, NL_VALIDATE_LIBERAL, extack);
907 }
908 
909 
910 
911 /**
912  * nlmsg_report - need to report back to application?
913  * @nlh: netlink message header
914  *
915  * Returns 1 if a report back to the application is requested.
916  */
917 static inline int nlmsg_report(const struct nlmsghdr *nlh)
918 {
919 	return nlh ? !!(nlh->nlmsg_flags & NLM_F_ECHO) : 0;
920 }
921 
922 /**
923  * nlmsg_seq - return the seq number of netlink message
924  * @nlh: netlink message header
925  *
926  * Returns 0 if netlink message is NULL
927  */
928 static inline u32 nlmsg_seq(const struct nlmsghdr *nlh)
929 {
930 	return nlh ? nlh->nlmsg_seq : 0;
931 }
932 
933 /**
934  * nlmsg_for_each_attr - iterate over a stream of attributes
935  * @pos: loop counter, set to current attribute
936  * @nlh: netlink message header
937  * @hdrlen: length of family specific header
938  * @rem: initialized to len, holds bytes currently remaining in stream
939  */
940 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
941 	nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
942 			  nlmsg_attrlen(nlh, hdrlen), rem)
943 
944 /**
945  * nlmsg_put - Add a new netlink message to an skb
946  * @skb: socket buffer to store message in
947  * @portid: netlink PORTID of requesting application
948  * @seq: sequence number of message
949  * @type: message type
950  * @payload: length of message payload
951  * @flags: message flags
952  *
953  * Returns NULL if the tailroom of the skb is insufficient to store
954  * the message header and payload.
955  */
956 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
957 					 int type, int payload, int flags)
958 {
959 	if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
960 		return NULL;
961 
962 	return __nlmsg_put(skb, portid, seq, type, payload, flags);
963 }
964 
965 /**
966  * nlmsg_append - Add more data to a nlmsg in a skb
967  * @skb: socket buffer to store message in
968  * @size: length of message payload
969  *
970  * Append data to an existing nlmsg, used when constructing a message
971  * with multiple fixed-format headers (which is rare).
972  * Returns NULL if the tailroom of the skb is insufficient to store
973  * the extra payload.
974  */
975 static inline void *nlmsg_append(struct sk_buff *skb, u32 size)
976 {
977 	if (unlikely(skb_tailroom(skb) < NLMSG_ALIGN(size)))
978 		return NULL;
979 
980 	if (NLMSG_ALIGN(size) - size)
981 		memset(skb_tail_pointer(skb) + size, 0,
982 		       NLMSG_ALIGN(size) - size);
983 	return __skb_put(skb, NLMSG_ALIGN(size));
984 }
985 
986 /**
987  * nlmsg_put_answer - Add a new callback based netlink message to an skb
988  * @skb: socket buffer to store message in
989  * @cb: netlink callback
990  * @type: message type
991  * @payload: length of message payload
992  * @flags: message flags
993  *
994  * Returns NULL if the tailroom of the skb is insufficient to store
995  * the message header and payload.
996  */
997 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
998 						struct netlink_callback *cb,
999 						int type, int payload,
1000 						int flags)
1001 {
1002 	return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
1003 			 type, payload, flags);
1004 }
1005 
1006 /**
1007  * nlmsg_new - Allocate a new netlink message
1008  * @payload: size of the message payload
1009  * @flags: the type of memory to allocate.
1010  *
1011  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
1012  * and a good default is needed.
1013  */
1014 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
1015 {
1016 	return alloc_skb(nlmsg_total_size(payload), flags);
1017 }
1018 
1019 /**
1020  * nlmsg_new_large - Allocate a new netlink message with non-contiguous
1021  * physical memory
1022  * @payload: size of the message payload
1023  *
1024  * The allocated skb is unable to have frag page for shinfo->frags*,
1025  * as the NULL setting for skb->head in netlink_skb_destructor() will
1026  * bypass most of the handling in skb_release_data()
1027  */
1028 static inline struct sk_buff *nlmsg_new_large(size_t payload)
1029 {
1030 	return netlink_alloc_large_skb(nlmsg_total_size(payload), 0);
1031 }
1032 
1033 /**
1034  * nlmsg_end - Finalize a netlink message
1035  * @skb: socket buffer the message is stored in
1036  * @nlh: netlink message header
1037  *
1038  * Corrects the netlink message header to include the appended
1039  * attributes. Only necessary if attributes have been added to
1040  * the message.
1041  */
1042 static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
1043 {
1044 	nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
1045 }
1046 
1047 /**
1048  * nlmsg_get_pos - return current position in netlink message
1049  * @skb: socket buffer the message is stored in
1050  *
1051  * Returns a pointer to the current tail of the message.
1052  */
1053 static inline void *nlmsg_get_pos(struct sk_buff *skb)
1054 {
1055 	return skb_tail_pointer(skb);
1056 }
1057 
1058 /**
1059  * nlmsg_trim - Trim message to a mark
1060  * @skb: socket buffer the message is stored in
1061  * @mark: mark to trim to
1062  *
1063  * Trims the message to the provided mark.
1064  */
1065 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
1066 {
1067 	if (mark) {
1068 		WARN_ON((unsigned char *) mark < skb->data);
1069 		skb_trim(skb, (unsigned char *) mark - skb->data);
1070 	}
1071 }
1072 
1073 /**
1074  * nlmsg_cancel - Cancel construction of a netlink message
1075  * @skb: socket buffer the message is stored in
1076  * @nlh: netlink message header
1077  *
1078  * Removes the complete netlink message including all
1079  * attributes from the socket buffer again.
1080  */
1081 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
1082 {
1083 	nlmsg_trim(skb, nlh);
1084 }
1085 
1086 /**
1087  * nlmsg_free - drop a netlink message
1088  * @skb: socket buffer of netlink message
1089  */
1090 static inline void nlmsg_free(struct sk_buff *skb)
1091 {
1092 	kfree_skb(skb);
1093 }
1094 
1095 /**
1096  * nlmsg_consume - free a netlink message
1097  * @skb: socket buffer of netlink message
1098  */
1099 static inline void nlmsg_consume(struct sk_buff *skb)
1100 {
1101 	consume_skb(skb);
1102 }
1103 
1104 /**
1105  * nlmsg_multicast_filtered - multicast a netlink message with filter function
1106  * @sk: netlink socket to spread messages to
1107  * @skb: netlink message as socket buffer
1108  * @portid: own netlink portid to avoid sending to yourself
1109  * @group: multicast group id
1110  * @flags: allocation flags
1111  * @filter: filter function
1112  * @filter_data: filter function private data
1113  *
1114  * Return: 0 on success, negative error code for failure.
1115  */
1116 static inline int nlmsg_multicast_filtered(struct sock *sk, struct sk_buff *skb,
1117 					   u32 portid, unsigned int group,
1118 					   gfp_t flags,
1119 					   netlink_filter_fn filter,
1120 					   void *filter_data)
1121 {
1122 	int err;
1123 
1124 	NETLINK_CB(skb).dst_group = group;
1125 
1126 	err = netlink_broadcast_filtered(sk, skb, portid, group, flags,
1127 					 filter, filter_data);
1128 	if (err > 0)
1129 		err = 0;
1130 
1131 	return err;
1132 }
1133 
1134 /**
1135  * nlmsg_multicast - multicast a netlink message
1136  * @sk: netlink socket to spread messages to
1137  * @skb: netlink message as socket buffer
1138  * @portid: own netlink portid to avoid sending to yourself
1139  * @group: multicast group id
1140  * @flags: allocation flags
1141  */
1142 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
1143 				  u32 portid, unsigned int group, gfp_t flags)
1144 {
1145 	return nlmsg_multicast_filtered(sk, skb, portid, group, flags,
1146 					NULL, NULL);
1147 }
1148 
1149 /**
1150  * nlmsg_unicast - unicast a netlink message
1151  * @sk: netlink socket to spread message to
1152  * @skb: netlink message as socket buffer
1153  * @portid: netlink portid of the destination socket
1154  */
1155 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
1156 {
1157 	int err;
1158 
1159 	err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
1160 	if (err > 0)
1161 		err = 0;
1162 
1163 	return err;
1164 }
1165 
1166 /**
1167  * nlmsg_for_each_msg - iterate over a stream of messages
1168  * @pos: loop counter, set to current message
1169  * @head: head of message stream
1170  * @len: length of message stream
1171  * @rem: initialized to len, holds bytes currently remaining in stream
1172  */
1173 #define nlmsg_for_each_msg(pos, head, len, rem) \
1174 	for (pos = head, rem = len; \
1175 	     nlmsg_ok(pos, rem); \
1176 	     pos = nlmsg_next(pos, &(rem)))
1177 
1178 /**
1179  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
1180  * @cb: netlink callback structure that stores the sequence number
1181  * @nlh: netlink message header to write the flag to
1182  *
1183  * This function checks if the sequence (generation) number changed during dump
1184  * and if it did, advertises it in the netlink message header.
1185  *
1186  * The correct way to use it is to set cb->seq to the generation counter when
1187  * all locks for dumping have been acquired, and then call this function for
1188  * each message that is generated.
1189  *
1190  * Note that due to initialisation concerns, 0 is an invalid sequence number
1191  * and must not be used by code that uses this functionality.
1192  */
1193 static inline void
1194 nl_dump_check_consistent(struct netlink_callback *cb,
1195 			 struct nlmsghdr *nlh)
1196 {
1197 	if (cb->prev_seq && cb->seq != cb->prev_seq)
1198 		nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
1199 	cb->prev_seq = cb->seq;
1200 }
1201 
1202 /**************************************************************************
1203  * Netlink Attributes
1204  **************************************************************************/
1205 
1206 /**
1207  * nla_attr_size - length of attribute not including padding
1208  * @payload: length of payload
1209  */
1210 static inline int nla_attr_size(int payload)
1211 {
1212 	return NLA_HDRLEN + payload;
1213 }
1214 
1215 /**
1216  * nla_total_size - total length of attribute including padding
1217  * @payload: length of payload
1218  */
1219 static inline int nla_total_size(int payload)
1220 {
1221 	return NLA_ALIGN(nla_attr_size(payload));
1222 }
1223 
1224 /**
1225  * nla_padlen - length of padding at the tail of attribute
1226  * @payload: length of payload
1227  */
1228 static inline int nla_padlen(int payload)
1229 {
1230 	return nla_total_size(payload) - nla_attr_size(payload);
1231 }
1232 
1233 /**
1234  * nla_type - attribute type
1235  * @nla: netlink attribute
1236  */
1237 static inline int nla_type(const struct nlattr *nla)
1238 {
1239 	return nla->nla_type & NLA_TYPE_MASK;
1240 }
1241 
1242 /**
1243  * nla_data - head of payload
1244  * @nla: netlink attribute
1245  */
1246 static inline void *nla_data(const struct nlattr *nla)
1247 {
1248 	return (char *) nla + NLA_HDRLEN;
1249 }
1250 
1251 /**
1252  * nla_len - length of payload
1253  * @nla: netlink attribute
1254  */
1255 static inline u16 nla_len(const struct nlattr *nla)
1256 {
1257 	return nla->nla_len - NLA_HDRLEN;
1258 }
1259 
1260 /**
1261  * nla_ok - check if the netlink attribute fits into the remaining bytes
1262  * @nla: netlink attribute
1263  * @remaining: number of bytes remaining in attribute stream
1264  */
1265 static inline int nla_ok(const struct nlattr *nla, int remaining)
1266 {
1267 	return remaining >= (int) sizeof(*nla) &&
1268 	       nla->nla_len >= sizeof(*nla) &&
1269 	       nla->nla_len <= remaining;
1270 }
1271 
1272 /**
1273  * nla_next - next netlink attribute in attribute stream
1274  * @nla: netlink attribute
1275  * @remaining: number of bytes remaining in attribute stream
1276  *
1277  * Returns the next netlink attribute in the attribute stream and
1278  * decrements remaining by the size of the current attribute.
1279  */
1280 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
1281 {
1282 	unsigned int totlen = NLA_ALIGN(nla->nla_len);
1283 
1284 	*remaining -= totlen;
1285 	return (struct nlattr *) ((char *) nla + totlen);
1286 }
1287 
1288 /**
1289  * nla_find_nested - find attribute in a set of nested attributes
1290  * @nla: attribute containing the nested attributes
1291  * @attrtype: type of attribute to look for
1292  *
1293  * Returns the first attribute which matches the specified type.
1294  */
1295 static inline struct nlattr *
1296 nla_find_nested(const struct nlattr *nla, int attrtype)
1297 {
1298 	return nla_find(nla_data(nla), nla_len(nla), attrtype);
1299 }
1300 
1301 /**
1302  * nla_parse_nested - parse nested attributes
1303  * @tb: destination array with maxtype+1 elements
1304  * @maxtype: maximum attribute type to be expected
1305  * @nla: attribute containing the nested attributes
1306  * @policy: validation policy
1307  * @extack: extended ACK report struct
1308  *
1309  * See nla_parse()
1310  */
1311 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
1312 				   const struct nlattr *nla,
1313 				   const struct nla_policy *policy,
1314 				   struct netlink_ext_ack *extack)
1315 {
1316 	if (!(nla->nla_type & NLA_F_NESTED)) {
1317 		NL_SET_ERR_MSG_ATTR(extack, nla, "NLA_F_NESTED is missing");
1318 		return -EINVAL;
1319 	}
1320 
1321 	return __nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy,
1322 			   NL_VALIDATE_STRICT, extack);
1323 }
1324 
1325 /**
1326  * nla_parse_nested_deprecated - parse nested attributes
1327  * @tb: destination array with maxtype+1 elements
1328  * @maxtype: maximum attribute type to be expected
1329  * @nla: attribute containing the nested attributes
1330  * @policy: validation policy
1331  * @extack: extended ACK report struct
1332  *
1333  * See nla_parse_deprecated()
1334  */
1335 static inline int nla_parse_nested_deprecated(struct nlattr *tb[], int maxtype,
1336 					      const struct nlattr *nla,
1337 					      const struct nla_policy *policy,
1338 					      struct netlink_ext_ack *extack)
1339 {
1340 	return __nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy,
1341 			   NL_VALIDATE_LIBERAL, extack);
1342 }
1343 
1344 /**
1345  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
1346  * @skb: socket buffer to add attribute to
1347  * @attrtype: attribute type
1348  * @value: numeric value
1349  */
1350 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
1351 {
1352 	/* temporary variables to work around GCC PR81715 with asan-stack=1 */
1353 	u8 tmp = value;
1354 
1355 	return nla_put(skb, attrtype, sizeof(u8), &tmp);
1356 }
1357 
1358 /**
1359  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
1360  * @skb: socket buffer to add attribute to
1361  * @attrtype: attribute type
1362  * @value: numeric value
1363  */
1364 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
1365 {
1366 	u16 tmp = value;
1367 
1368 	return nla_put(skb, attrtype, sizeof(u16), &tmp);
1369 }
1370 
1371 /**
1372  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
1373  * @skb: socket buffer to add attribute to
1374  * @attrtype: attribute type
1375  * @value: numeric value
1376  */
1377 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
1378 {
1379 	__be16 tmp = value;
1380 
1381 	return nla_put(skb, attrtype, sizeof(__be16), &tmp);
1382 }
1383 
1384 /**
1385  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
1386  * @skb: socket buffer to add attribute to
1387  * @attrtype: attribute type
1388  * @value: numeric value
1389  */
1390 static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
1391 {
1392 	__be16 tmp = value;
1393 
1394 	return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, tmp);
1395 }
1396 
1397 /**
1398  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
1399  * @skb: socket buffer to add attribute to
1400  * @attrtype: attribute type
1401  * @value: numeric value
1402  */
1403 static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
1404 {
1405 	__le16 tmp = value;
1406 
1407 	return nla_put(skb, attrtype, sizeof(__le16), &tmp);
1408 }
1409 
1410 /**
1411  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
1412  * @skb: socket buffer to add attribute to
1413  * @attrtype: attribute type
1414  * @value: numeric value
1415  */
1416 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
1417 {
1418 	u32 tmp = value;
1419 
1420 	return nla_put(skb, attrtype, sizeof(u32), &tmp);
1421 }
1422 
1423 /**
1424  * nla_put_uint - Add a variable-size unsigned int to a socket buffer
1425  * @skb: socket buffer to add attribute to
1426  * @attrtype: attribute type
1427  * @value: numeric value
1428  */
1429 static inline int nla_put_uint(struct sk_buff *skb, int attrtype, u64 value)
1430 {
1431 	u64 tmp64 = value;
1432 	u32 tmp32 = value;
1433 
1434 	if (tmp64 == tmp32)
1435 		return nla_put_u32(skb, attrtype, tmp32);
1436 	return nla_put(skb, attrtype, sizeof(u64), &tmp64);
1437 }
1438 
1439 /**
1440  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
1441  * @skb: socket buffer to add attribute to
1442  * @attrtype: attribute type
1443  * @value: numeric value
1444  */
1445 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
1446 {
1447 	__be32 tmp = value;
1448 
1449 	return nla_put(skb, attrtype, sizeof(__be32), &tmp);
1450 }
1451 
1452 /**
1453  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
1454  * @skb: socket buffer to add attribute to
1455  * @attrtype: attribute type
1456  * @value: numeric value
1457  */
1458 static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
1459 {
1460 	__be32 tmp = value;
1461 
1462 	return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, tmp);
1463 }
1464 
1465 /**
1466  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
1467  * @skb: socket buffer to add attribute to
1468  * @attrtype: attribute type
1469  * @value: numeric value
1470  */
1471 static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
1472 {
1473 	__le32 tmp = value;
1474 
1475 	return nla_put(skb, attrtype, sizeof(__le32), &tmp);
1476 }
1477 
1478 /**
1479  * nla_put_u64_64bit - Add a u64 netlink attribute to a skb and align it
1480  * @skb: socket buffer to add attribute to
1481  * @attrtype: attribute type
1482  * @value: numeric value
1483  * @padattr: attribute type for the padding
1484  */
1485 static inline int nla_put_u64_64bit(struct sk_buff *skb, int attrtype,
1486 				    u64 value, int padattr)
1487 {
1488 	u64 tmp = value;
1489 
1490 	return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
1491 }
1492 
1493 /**
1494  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
1495  * @skb: socket buffer to add attribute to
1496  * @attrtype: attribute type
1497  * @value: numeric value
1498  * @padattr: attribute type for the padding
1499  */
1500 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value,
1501 			       int padattr)
1502 {
1503 	__be64 tmp = value;
1504 
1505 	return nla_put_64bit(skb, attrtype, sizeof(__be64), &tmp, padattr);
1506 }
1507 
1508 /**
1509  * nla_put_net64 - Add 64-bit network byte order nlattr to a skb and align it
1510  * @skb: socket buffer to add attribute to
1511  * @attrtype: attribute type
1512  * @value: numeric value
1513  * @padattr: attribute type for the padding
1514  */
1515 static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value,
1516 				int padattr)
1517 {
1518 	__be64 tmp = value;
1519 
1520 	return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, tmp,
1521 			    padattr);
1522 }
1523 
1524 /**
1525  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
1526  * @skb: socket buffer to add attribute to
1527  * @attrtype: attribute type
1528  * @value: numeric value
1529  * @padattr: attribute type for the padding
1530  */
1531 static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value,
1532 			       int padattr)
1533 {
1534 	__le64 tmp = value;
1535 
1536 	return nla_put_64bit(skb, attrtype, sizeof(__le64), &tmp, padattr);
1537 }
1538 
1539 /**
1540  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
1541  * @skb: socket buffer to add attribute to
1542  * @attrtype: attribute type
1543  * @value: numeric value
1544  */
1545 static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
1546 {
1547 	s8 tmp = value;
1548 
1549 	return nla_put(skb, attrtype, sizeof(s8), &tmp);
1550 }
1551 
1552 /**
1553  * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
1554  * @skb: socket buffer to add attribute to
1555  * @attrtype: attribute type
1556  * @value: numeric value
1557  */
1558 static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
1559 {
1560 	s16 tmp = value;
1561 
1562 	return nla_put(skb, attrtype, sizeof(s16), &tmp);
1563 }
1564 
1565 /**
1566  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
1567  * @skb: socket buffer to add attribute to
1568  * @attrtype: attribute type
1569  * @value: numeric value
1570  */
1571 static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
1572 {
1573 	s32 tmp = value;
1574 
1575 	return nla_put(skb, attrtype, sizeof(s32), &tmp);
1576 }
1577 
1578 /**
1579  * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
1580  * @skb: socket buffer to add attribute to
1581  * @attrtype: attribute type
1582  * @value: numeric value
1583  * @padattr: attribute type for the padding
1584  */
1585 static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value,
1586 			      int padattr)
1587 {
1588 	s64 tmp = value;
1589 
1590 	return nla_put_64bit(skb, attrtype, sizeof(s64), &tmp, padattr);
1591 }
1592 
1593 /**
1594  * nla_put_sint - Add a variable-size signed int to a socket buffer
1595  * @skb: socket buffer to add attribute to
1596  * @attrtype: attribute type
1597  * @value: numeric value
1598  */
1599 static inline int nla_put_sint(struct sk_buff *skb, int attrtype, s64 value)
1600 {
1601 	s64 tmp64 = value;
1602 	s32 tmp32 = value;
1603 
1604 	if (tmp64 == tmp32)
1605 		return nla_put_s32(skb, attrtype, tmp32);
1606 	return nla_put(skb, attrtype, sizeof(s64), &tmp64);
1607 }
1608 
1609 /**
1610  * nla_put_string - Add a string netlink attribute to a socket buffer
1611  * @skb: socket buffer to add attribute to
1612  * @attrtype: attribute type
1613  * @str: NUL terminated string
1614  */
1615 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
1616 				 const char *str)
1617 {
1618 	return nla_put(skb, attrtype, strlen(str) + 1, str);
1619 }
1620 
1621 /**
1622  * nla_put_flag - Add a flag netlink attribute to a socket buffer
1623  * @skb: socket buffer to add attribute to
1624  * @attrtype: attribute type
1625  */
1626 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
1627 {
1628 	return nla_put(skb, attrtype, 0, NULL);
1629 }
1630 
1631 /**
1632  * nla_put_msecs - Add a msecs netlink attribute to a skb and align it
1633  * @skb: socket buffer to add attribute to
1634  * @attrtype: attribute type
1635  * @njiffies: number of jiffies to convert to msecs
1636  * @padattr: attribute type for the padding
1637  */
1638 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
1639 				unsigned long njiffies, int padattr)
1640 {
1641 	u64 tmp = jiffies_to_msecs(njiffies);
1642 
1643 	return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
1644 }
1645 
1646 /**
1647  * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
1648  * buffer
1649  * @skb: socket buffer to add attribute to
1650  * @attrtype: attribute type
1651  * @addr: IPv4 address
1652  */
1653 static inline int nla_put_in_addr(struct sk_buff *skb, int attrtype,
1654 				  __be32 addr)
1655 {
1656 	__be32 tmp = addr;
1657 
1658 	return nla_put_be32(skb, attrtype, tmp);
1659 }
1660 
1661 /**
1662  * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
1663  * buffer
1664  * @skb: socket buffer to add attribute to
1665  * @attrtype: attribute type
1666  * @addr: IPv6 address
1667  */
1668 static inline int nla_put_in6_addr(struct sk_buff *skb, int attrtype,
1669 				   const struct in6_addr *addr)
1670 {
1671 	return nla_put(skb, attrtype, sizeof(*addr), addr);
1672 }
1673 
1674 /**
1675  * nla_put_bitfield32 - Add a bitfield32 netlink attribute to a socket buffer
1676  * @skb: socket buffer to add attribute to
1677  * @attrtype: attribute type
1678  * @value: value carrying bits
1679  * @selector: selector of valid bits
1680  */
1681 static inline int nla_put_bitfield32(struct sk_buff *skb, int attrtype,
1682 				     __u32 value, __u32 selector)
1683 {
1684 	struct nla_bitfield32 tmp = { value, selector, };
1685 
1686 	return nla_put(skb, attrtype, sizeof(tmp), &tmp);
1687 }
1688 
1689 /**
1690  * nla_get_u32 - return payload of u32 attribute
1691  * @nla: u32 netlink attribute
1692  */
1693 static inline u32 nla_get_u32(const struct nlattr *nla)
1694 {
1695 	return *(u32 *) nla_data(nla);
1696 }
1697 
1698 /**
1699  * nla_get_be32 - return payload of __be32 attribute
1700  * @nla: __be32 netlink attribute
1701  */
1702 static inline __be32 nla_get_be32(const struct nlattr *nla)
1703 {
1704 	return *(__be32 *) nla_data(nla);
1705 }
1706 
1707 /**
1708  * nla_get_le32 - return payload of __le32 attribute
1709  * @nla: __le32 netlink attribute
1710  */
1711 static inline __le32 nla_get_le32(const struct nlattr *nla)
1712 {
1713 	return *(__le32 *) nla_data(nla);
1714 }
1715 
1716 /**
1717  * nla_get_u16 - return payload of u16 attribute
1718  * @nla: u16 netlink attribute
1719  */
1720 static inline u16 nla_get_u16(const struct nlattr *nla)
1721 {
1722 	return *(u16 *) nla_data(nla);
1723 }
1724 
1725 /**
1726  * nla_get_be16 - return payload of __be16 attribute
1727  * @nla: __be16 netlink attribute
1728  */
1729 static inline __be16 nla_get_be16(const struct nlattr *nla)
1730 {
1731 	return *(__be16 *) nla_data(nla);
1732 }
1733 
1734 /**
1735  * nla_get_le16 - return payload of __le16 attribute
1736  * @nla: __le16 netlink attribute
1737  */
1738 static inline __le16 nla_get_le16(const struct nlattr *nla)
1739 {
1740 	return *(__le16 *) nla_data(nla);
1741 }
1742 
1743 /**
1744  * nla_get_u8 - return payload of u8 attribute
1745  * @nla: u8 netlink attribute
1746  */
1747 static inline u8 nla_get_u8(const struct nlattr *nla)
1748 {
1749 	return *(u8 *) nla_data(nla);
1750 }
1751 
1752 /**
1753  * nla_get_u64 - return payload of u64 attribute
1754  * @nla: u64 netlink attribute
1755  */
1756 static inline u64 nla_get_u64(const struct nlattr *nla)
1757 {
1758 	u64 tmp;
1759 
1760 	nla_memcpy(&tmp, nla, sizeof(tmp));
1761 
1762 	return tmp;
1763 }
1764 
1765 /**
1766  * nla_get_uint - return payload of uint attribute
1767  * @nla: uint netlink attribute
1768  */
1769 static inline u64 nla_get_uint(const struct nlattr *nla)
1770 {
1771 	if (nla_len(nla) == sizeof(u32))
1772 		return nla_get_u32(nla);
1773 	return nla_get_u64(nla);
1774 }
1775 
1776 /**
1777  * nla_get_be64 - return payload of __be64 attribute
1778  * @nla: __be64 netlink attribute
1779  */
1780 static inline __be64 nla_get_be64(const struct nlattr *nla)
1781 {
1782 	__be64 tmp;
1783 
1784 	nla_memcpy(&tmp, nla, sizeof(tmp));
1785 
1786 	return tmp;
1787 }
1788 
1789 /**
1790  * nla_get_le64 - return payload of __le64 attribute
1791  * @nla: __le64 netlink attribute
1792  */
1793 static inline __le64 nla_get_le64(const struct nlattr *nla)
1794 {
1795 	return *(__le64 *) nla_data(nla);
1796 }
1797 
1798 /**
1799  * nla_get_s32 - return payload of s32 attribute
1800  * @nla: s32 netlink attribute
1801  */
1802 static inline s32 nla_get_s32(const struct nlattr *nla)
1803 {
1804 	return *(s32 *) nla_data(nla);
1805 }
1806 
1807 /**
1808  * nla_get_s16 - return payload of s16 attribute
1809  * @nla: s16 netlink attribute
1810  */
1811 static inline s16 nla_get_s16(const struct nlattr *nla)
1812 {
1813 	return *(s16 *) nla_data(nla);
1814 }
1815 
1816 /**
1817  * nla_get_s8 - return payload of s8 attribute
1818  * @nla: s8 netlink attribute
1819  */
1820 static inline s8 nla_get_s8(const struct nlattr *nla)
1821 {
1822 	return *(s8 *) nla_data(nla);
1823 }
1824 
1825 /**
1826  * nla_get_s64 - return payload of s64 attribute
1827  * @nla: s64 netlink attribute
1828  */
1829 static inline s64 nla_get_s64(const struct nlattr *nla)
1830 {
1831 	s64 tmp;
1832 
1833 	nla_memcpy(&tmp, nla, sizeof(tmp));
1834 
1835 	return tmp;
1836 }
1837 
1838 /**
1839  * nla_get_sint - return payload of uint attribute
1840  * @nla: uint netlink attribute
1841  */
1842 static inline s64 nla_get_sint(const struct nlattr *nla)
1843 {
1844 	if (nla_len(nla) == sizeof(s32))
1845 		return nla_get_s32(nla);
1846 	return nla_get_s64(nla);
1847 }
1848 
1849 /**
1850  * nla_get_flag - return payload of flag attribute
1851  * @nla: flag netlink attribute
1852  */
1853 static inline int nla_get_flag(const struct nlattr *nla)
1854 {
1855 	return !!nla;
1856 }
1857 
1858 /**
1859  * nla_get_msecs - return payload of msecs attribute
1860  * @nla: msecs netlink attribute
1861  *
1862  * Returns the number of milliseconds in jiffies.
1863  */
1864 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1865 {
1866 	u64 msecs = nla_get_u64(nla);
1867 
1868 	return msecs_to_jiffies((unsigned long) msecs);
1869 }
1870 
1871 /**
1872  * nla_get_in_addr - return payload of IPv4 address attribute
1873  * @nla: IPv4 address netlink attribute
1874  */
1875 static inline __be32 nla_get_in_addr(const struct nlattr *nla)
1876 {
1877 	return *(__be32 *) nla_data(nla);
1878 }
1879 
1880 /**
1881  * nla_get_in6_addr - return payload of IPv6 address attribute
1882  * @nla: IPv6 address netlink attribute
1883  */
1884 static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
1885 {
1886 	struct in6_addr tmp;
1887 
1888 	nla_memcpy(&tmp, nla, sizeof(tmp));
1889 	return tmp;
1890 }
1891 
1892 /**
1893  * nla_get_bitfield32 - return payload of 32 bitfield attribute
1894  * @nla: nla_bitfield32 attribute
1895  */
1896 static inline struct nla_bitfield32 nla_get_bitfield32(const struct nlattr *nla)
1897 {
1898 	struct nla_bitfield32 tmp;
1899 
1900 	nla_memcpy(&tmp, nla, sizeof(tmp));
1901 	return tmp;
1902 }
1903 
1904 /**
1905  * nla_memdup - duplicate attribute memory (kmemdup)
1906  * @src: netlink attribute to duplicate from
1907  * @gfp: GFP mask
1908  */
1909 static inline void *nla_memdup_noprof(const struct nlattr *src, gfp_t gfp)
1910 {
1911 	return kmemdup_noprof(nla_data(src), nla_len(src), gfp);
1912 }
1913 #define nla_memdup(...)	alloc_hooks(nla_memdup_noprof(__VA_ARGS__))
1914 
1915 /**
1916  * nla_nest_start_noflag - Start a new level of nested attributes
1917  * @skb: socket buffer to add attributes to
1918  * @attrtype: attribute type of container
1919  *
1920  * This function exists for backward compatibility to use in APIs which never
1921  * marked their nest attributes with NLA_F_NESTED flag. New APIs should use
1922  * nla_nest_start() which sets the flag.
1923  *
1924  * Returns the container attribute or NULL on error
1925  */
1926 static inline struct nlattr *nla_nest_start_noflag(struct sk_buff *skb,
1927 						   int attrtype)
1928 {
1929 	struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1930 
1931 	if (nla_put(skb, attrtype, 0, NULL) < 0)
1932 		return NULL;
1933 
1934 	return start;
1935 }
1936 
1937 /**
1938  * nla_nest_start - Start a new level of nested attributes, with NLA_F_NESTED
1939  * @skb: socket buffer to add attributes to
1940  * @attrtype: attribute type of container
1941  *
1942  * Unlike nla_nest_start_noflag(), mark the nest attribute with NLA_F_NESTED
1943  * flag. This is the preferred function to use in new code.
1944  *
1945  * Returns the container attribute or NULL on error
1946  */
1947 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1948 {
1949 	return nla_nest_start_noflag(skb, attrtype | NLA_F_NESTED);
1950 }
1951 
1952 /**
1953  * nla_nest_end - Finalize nesting of attributes
1954  * @skb: socket buffer the attributes are stored in
1955  * @start: container attribute
1956  *
1957  * Corrects the container attribute header to include the all
1958  * appended attributes.
1959  *
1960  * Returns the total data length of the skb.
1961  */
1962 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1963 {
1964 	start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1965 	return skb->len;
1966 }
1967 
1968 /**
1969  * nla_nest_cancel - Cancel nesting of attributes
1970  * @skb: socket buffer the message is stored in
1971  * @start: container attribute
1972  *
1973  * Removes the container attribute and including all nested
1974  * attributes. Returns -EMSGSIZE
1975  */
1976 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1977 {
1978 	nlmsg_trim(skb, start);
1979 }
1980 
1981 /**
1982  * __nla_validate_nested - Validate a stream of nested attributes
1983  * @start: container attribute
1984  * @maxtype: maximum attribute type to be expected
1985  * @policy: validation policy
1986  * @validate: validation strictness
1987  * @extack: extended ACK report struct
1988  *
1989  * Validates all attributes in the nested attribute stream against the
1990  * specified policy. Attributes with a type exceeding maxtype will be
1991  * ignored. See documentation of struct nla_policy for more details.
1992  *
1993  * Returns 0 on success or a negative error code.
1994  */
1995 static inline int __nla_validate_nested(const struct nlattr *start, int maxtype,
1996 					const struct nla_policy *policy,
1997 					unsigned int validate,
1998 					struct netlink_ext_ack *extack)
1999 {
2000 	return __nla_validate(nla_data(start), nla_len(start), maxtype, policy,
2001 			      validate, extack);
2002 }
2003 
2004 static inline int
2005 nla_validate_nested(const struct nlattr *start, int maxtype,
2006 		    const struct nla_policy *policy,
2007 		    struct netlink_ext_ack *extack)
2008 {
2009 	return __nla_validate_nested(start, maxtype, policy,
2010 				     NL_VALIDATE_STRICT, extack);
2011 }
2012 
2013 static inline int
2014 nla_validate_nested_deprecated(const struct nlattr *start, int maxtype,
2015 			       const struct nla_policy *policy,
2016 			       struct netlink_ext_ack *extack)
2017 {
2018 	return __nla_validate_nested(start, maxtype, policy,
2019 				     NL_VALIDATE_LIBERAL, extack);
2020 }
2021 
2022 /**
2023  * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
2024  * @skb: socket buffer the message is stored in
2025  *
2026  * Return true if padding is needed to align the next attribute (nla_data()) to
2027  * a 64-bit aligned area.
2028  */
2029 static inline bool nla_need_padding_for_64bit(struct sk_buff *skb)
2030 {
2031 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
2032 	/* The nlattr header is 4 bytes in size, that's why we test
2033 	 * if the skb->data _is_ aligned.  A NOP attribute, plus
2034 	 * nlattr header for next attribute, will make nla_data()
2035 	 * 8-byte aligned.
2036 	 */
2037 	if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))
2038 		return true;
2039 #endif
2040 	return false;
2041 }
2042 
2043 /**
2044  * nla_align_64bit - 64-bit align the nla_data() of next attribute
2045  * @skb: socket buffer the message is stored in
2046  * @padattr: attribute type for the padding
2047  *
2048  * Conditionally emit a padding netlink attribute in order to make
2049  * the next attribute we emit have a 64-bit aligned nla_data() area.
2050  * This will only be done in architectures which do not have
2051  * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS defined.
2052  *
2053  * Returns zero on success or a negative error code.
2054  */
2055 static inline int nla_align_64bit(struct sk_buff *skb, int padattr)
2056 {
2057 	if (nla_need_padding_for_64bit(skb) &&
2058 	    !nla_reserve(skb, padattr, 0))
2059 		return -EMSGSIZE;
2060 
2061 	return 0;
2062 }
2063 
2064 /**
2065  * nla_total_size_64bit - total length of attribute including padding
2066  * @payload: length of payload
2067  */
2068 static inline int nla_total_size_64bit(int payload)
2069 {
2070 	return NLA_ALIGN(nla_attr_size(payload))
2071 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
2072 		+ NLA_ALIGN(nla_attr_size(0))
2073 #endif
2074 		;
2075 }
2076 
2077 /**
2078  * nla_for_each_attr - iterate over a stream of attributes
2079  * @pos: loop counter, set to current attribute
2080  * @head: head of attribute stream
2081  * @len: length of attribute stream
2082  * @rem: initialized to len, holds bytes currently remaining in stream
2083  */
2084 #define nla_for_each_attr(pos, head, len, rem) \
2085 	for (pos = head, rem = len; \
2086 	     nla_ok(pos, rem); \
2087 	     pos = nla_next(pos, &(rem)))
2088 
2089 /**
2090  * nla_for_each_attr_type - iterate over a stream of attributes
2091  * @pos: loop counter, set to current attribute
2092  * @type: required attribute type for @pos
2093  * @head: head of attribute stream
2094  * @len: length of attribute stream
2095  * @rem: initialized to len, holds bytes currently remaining in stream
2096  */
2097 #define nla_for_each_attr_type(pos, type, head, len, rem) \
2098 	nla_for_each_attr(pos, head, len, rem) \
2099 		if (nla_type(pos) == type)
2100 
2101 /**
2102  * nla_for_each_nested - iterate over nested attributes
2103  * @pos: loop counter, set to current attribute
2104  * @nla: attribute containing the nested attributes
2105  * @rem: initialized to len, holds bytes currently remaining in stream
2106  */
2107 #define nla_for_each_nested(pos, nla, rem) \
2108 	nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
2109 
2110 /**
2111  * nla_for_each_nested_type - iterate over nested attributes
2112  * @pos: loop counter, set to current attribute
2113  * @type: required attribute type for @pos
2114  * @nla: attribute containing the nested attributes
2115  * @rem: initialized to len, holds bytes currently remaining in stream
2116  */
2117 #define nla_for_each_nested_type(pos, type, nla, rem) \
2118 	nla_for_each_nested(pos, nla, rem) \
2119 		if (nla_type(pos) == type)
2120 
2121 /**
2122  * nla_is_last - Test if attribute is last in stream
2123  * @nla: attribute to test
2124  * @rem: bytes remaining in stream
2125  */
2126 static inline bool nla_is_last(const struct nlattr *nla, int rem)
2127 {
2128 	return nla->nla_len == rem;
2129 }
2130 
2131 void nla_get_range_unsigned(const struct nla_policy *pt,
2132 			    struct netlink_range_validation *range);
2133 void nla_get_range_signed(const struct nla_policy *pt,
2134 			  struct netlink_range_validation_signed *range);
2135 
2136 struct netlink_policy_dump_state;
2137 
2138 int netlink_policy_dump_add_policy(struct netlink_policy_dump_state **pstate,
2139 				   const struct nla_policy *policy,
2140 				   unsigned int maxtype);
2141 int netlink_policy_dump_get_policy_idx(struct netlink_policy_dump_state *state,
2142 				       const struct nla_policy *policy,
2143 				       unsigned int maxtype);
2144 bool netlink_policy_dump_loop(struct netlink_policy_dump_state *state);
2145 int netlink_policy_dump_write(struct sk_buff *skb,
2146 			      struct netlink_policy_dump_state *state);
2147 int netlink_policy_dump_attr_size_estimate(const struct nla_policy *pt);
2148 int netlink_policy_dump_write_attr(struct sk_buff *skb,
2149 				   const struct nla_policy *pt,
2150 				   int nestattr);
2151 void netlink_policy_dump_free(struct netlink_policy_dump_state *state);
2152 
2153 #endif
2154